1. Field of the Invention
This invention relates to a system for stabilizing a spinning spacecraft exposed to disturbing moments.
2. Description of Related Art
Spin stabilization is the simplest technique for controlling spacecraft attitude for spacecraft orbited around the earth. A spacecraft can be characterized as having three orthogonal moment of inertia axes which typically each have a unique moment of inertia value, thus defining a principal or maximum axis, a minimum axis, and an intermediate axis. Rotation about any axis presents stability concerns which are alleviated by the present invention.
As an alternative to rotating a spacecraft about an unstable axis or when subjected to destabilizing forces, a three-axis active control system can be used. These systems are complex, and are subject to gyro drift error which can lead to attitude inaccuracies.
Present nutation control systems for spinning spacecraft typically require nutation to reach a predetermined level before corrective thruster firing occurs and thus does not provide proportional attitude control. In some cases, this can cause loss of control.